Feed mechanism for a thread roller

ABSTRACT

A feed mechanism for thread roller apparatus where the feed slide is driven in a feeding direction by springs extending at a controlled rate, and retracted through a flexible cable which is tensioned by a return force exerted by a cam and cam controlled lever. Upon retraction, the springs have energy stored therein for the next feed stroke.

United States Patent 1191 1111 3, Pazdirek Dec. 3, 1974 [54] FEED MECHANISM FOR A THREAD 1,584,264 5/1926 Wilcox 72 90 ROLLER l,696,225 l2/l928 Blood 72/90 2,596,962 5/1952 Stern 72/90 5] n entor: Jiri V- P z Waterbury, Conn 3,314,261 4/l967 GIOhOSki ct al. lO/l65 x [73] Assignee: Textron, Inc., Providence, RI.

Primary ExaminerC. W. Lanham [22] Filed: 1973 Assistant Examiner-D. M. Gurley [21] A N 325 230 Attorney, Agent, or FirmDeLio and Montgomery 152 US. (:1 72/90, 72/88, 72/434, [57] ABSTRACT 72/437 72 440 A feed mechanism for thread roller apparatus where 51 Int. c1 B21d 17/04, B2lh 3/06 the feed slide is driven in a feeding direction y [58] Field of Search 72/88, 90, 104, 440, 445, Springs extending at a controlled rate, and retracted 72/434 435; 10 1 5; 22 27 through a flexible cable which is tensioned by a return force exerted by a cam and cam controlled lever. [56 References Cited Upon retraction, the springs have energy stored UNITED STATES PATENTS therein for the next feed stroke.

l,322,663 11 1919 Wenzel 72/435 x 5 Claims, 3 Drawing Figures i' wv 1 1: 5 6o 34 )7 45a 4 32 PATENIL; DEC 3:974

SHEET 10F 2 VHHWWT f x PATENTEL 31974 saw 2 BF 2 FEED MECHANISM FOR A THREAD ROLLER This invention relates to thread rolling apparatus and more particularly relates to a feed mechanism therefor.

In thread rolling machines, a blank or headed workpiece to have threads rolled thereon slides down a feed chute and at the bottom thereof a feed finger reciprocates in one direction to allow the blank to fall from the chute and then moves in the other direction to feed the blank between stationary and movable dies.

Such feed mechanisms are generally positively power-actuated and if any jamming or binding of the feed mechanism occurs serious damage to the feed mechanism may result.

The present invention provides a new and improved feed mechanism for a thread rolling machine which has low inertia on the driving or positioning stroke and which is returnable by means of a flexible connecting member of low mass which eliminates or greatly minimizes the possibility of damage to the equipment in the event of any binding thereof.

Briefly stated, the invention in one form thereof comprises a feed mechanism which is normally cyclically operated to permit a workpiece to slide from a feed chute to a position where a slide will move it between the two dies. The slide is retracted through a flexible cable while energy is stored in driving springs. Then the slide is permitted to advance in a feeding stroke under the influence of the springs at a controlled rate to push a workpiece between the dies as the movable die advances with respect to the stationary die.

An object of this invention is to provide a new and improved feed mechanism for apparatus of the type described.

Another object of this invention is to provide a feed mechanism for apparatus of the type described having a non-rigid connection between a drive member and a feeding slide.

A further object of this invention is to provide a new and improved apparatus for advancing and retracting a feed mechanism of the type described.

The features of the invention which are believed to be novel are set forth with particularity and distinctly claimed in the concluding portion of this specification. However, the invention. both as to its organization and operation, may best be appreciated by reference to the following detailed description taken in conjunction with the drawings, in which:

FIG. 1 is a perspective view ofa machine in which the invention is embodied;

FIG. 2 is a plan view of the feed mechanism of the apparatus of FIG. I; and

FIG. 3 is a view seen in the plane oflines 33 of FIG. 2.

Referring now to the drawings, a thread rolling machine is generally identified by the reference numeral in FIG. I and includes a feed chute 11 from which blanks in the form of cylindrical workpieces 12, which may or may not be headed, roll and/or slide from a hopper 13. The blanks are fed in between a stationary die 14 and a movable die 15. The dies 14 and 15 are each provided with parallel grooves cut to the size and shape of the thread. Die 14 is stationary while die 15 reciprocates and rolls a blank between the two dies. As the workpiece is forcibly rolled between the dies the threads are rolled into the workpiece.

The machine is generally driven from a power source (not shown) which drives a shaft 16 having a crank and adjustable pitman thereon (not shown) connected to operate to reciprocate movable die member or gate 15. The feeding mechanism is operated from a cam 17 on shaft 16 which acts on a lever assembly 18 pivotally mounted intermediate the ends thereof on a shaft 19 within sleeve 20 extending through a supporting wall 21. Lever assembly 18 includes a follower arm 22 having a cam follower 23 rotatably mounted thereon and an arm 24 having an adjustable connecting member 25 positioned thereon.

Mounted to wall 21 is a support or housing member 28 including, walls 29 and 30 having rods 31 and 32 mounted therein and extending therebetween. A slide member 33 is movable on member 28. Guide means which may be in the form of ball bushings 34 and 35 are mounted on slide 33 and receive therethrough guide rod 32. Another guide means in the form of a ball bushing 36 is mounted on slide 33 and receives guide rod 31 therethrough.

With the construction thus far described, slide 33 may reciprocate on guide rods 31 and 32 with respect to housing or support member 28. Slide 33 has mounted thereto and extending forward thereof an injecting finger 38 adapted to push a workpiece between dies 14 and 15. As shown in FIG. 2, finger 38 is in a retracted position which permits one workpiece 12 to slide from chute 11 onto die 15.

A manual return lever 40 is pivotal about a bolt 41 in web portion 42 of support 28 and may be pivoted to a position shown in broken line in FIG. 3 against the bias of a retaining spring 43 to engage a bolt 44 threaded in slide 33. Slide 33 is connected to lever arm 24 at coupling member 25 through a flexible member in the form of a wire rope 45 having an adaptor 46 at the end thereof including a threaded portion 47 received in a mating threaded socket 48 which is pivotally mounted about a pin 49 on slide 33.

Disposed about guide rods 31 and 32 are relatively stiff springs 50 and'5l, respectively. Spring 50 acts between guide member 36 and a seat 52 on the end of a sleeve 53 about rod 31. Spring 51 acts between guide member 35 and a seat 54 on the end of a sleeve 55 about guide rod 32. The springs 50 and 51, when energy is stored therein, will act to move slide 33 to the right as viewed in FIGS. 2 and 3. I

A spring 56 is disposed about sleeve 53 and acts between seat 52 and wall 30. A spring 57 is disposed about sleeve 55 and acts between seat 54 and wall 30. The springs 56 and 57 are less stiff than springs 50 and 51 and will act to move slide 33 when springs 50 and 51 are extended.

Slide 33 will thus move to the right under the influence of the springs when permitted to do so by cam 17, lever assembly 18 and flexible connection 45.

Cable 45 at one end thereof has an adaptor 45a connected to member 25 on lever arm 24. Member 25 may be adjusted in position on arm 24 by means of a bolt 58 threadably received through member 25. Member 25 is then clamped in position on arm 24 by means of bolt 58 passing therethrough.

A spring 59 is connected between a pin 60 fixed on the machine and the end of lever arm 24 to urge and maintain follower 23 into contact with cam 16.

As shown in FIG. 2, finger 38 on slide 33 has just been retracted to allow a workpiece to slide out of chute 11 onto die 15. At this point cam 17 is in a dwell position. As cam 17 rotates, follower roller 23 will be contacted by lesser radii points on the cam. Lever assembly 18 will rotate clockwise allowing the springs 50 and 51 and then sleeves 53 and 55 to drive slide 33 and finger 38 forward pushing the blank between the dies as lower die simultaneously advances across die 14. Slide 33 and finger 38 will then remain in a fixed position for a period of time determined by the constant smaller radius of cam 17 until such time as cam 17 again rotates to a position to pivot lever assembly 18 counterclockwise and retract slide 33.

Die 15 will advance across die 14 until the desired thread pattern defined by the dies is rolled on the blank and the blank is discharged at the right side (as viewed in FIG. 2) of the dies. During this time, slide 33 and finger 38 are in a dwell position, and as die 15 is retracted, lever assembly 18 will be pivoted counterclockwise causing retraction of slide 33 and finger 38 to the position shown in FIG. 2 where another blank may drop down for a rolling operation.

Slide 33 is pulled back through flexible cable 45 and in so doing springs 56 and 57 are first compressed and then the stiffer springs 50 and 51 are compressed to have energy stored therein to produce the driving operation on the feed stroke of the feed mechanism.

If at any time jamming should occur which would prevent movement of slide 33 there will be no rigid driving member tending to move drive slide 33 forward. Instead, slack would just develop in the cable 45. it is important to note that the cable 45 develops the most tension while in a retracted position acting against the bias of the drive springs. The cam 17 and lever assembly 18 may be considered as a means for restraining and controlling the rate at which the blanks are fed between the dies and further as controlling the rate of application of the driving force exerted on slide 33 by the drive springs.

The primary driving force on slide 33 as a blank is fed between the dies is provided by the springs which re- 7 lease energy at a rate determined by the configuration of cam 17. Rotation of cam 17 further retracts slide 33 and acting through cable 45 causes energy to be stored in the drive springs. This provides a low inertia, low mass drive. If, for any reason, jamming occurs on a feed stroke, cable 45 will go slack and there is no rigid driving member which would attempt to further advance slide 33.

It may thus be seen that the objects of the invention set forth above as well as those made apparent from the preceding description are efficiently attained. While preferred embodiments of the invention have been set forth for purposes of disclosure, other embodiments of the invention as well as modifications to the disclosed embodiment may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments of the invention which do not depart from the spirit and scope thereof.

What is claimed is:

l. A feed mechanism for a thread roller which includes first and second rolling dies, one of said dies being movable relative to the other, and a chute for delivering workpieces to a position for rolling between the dies, comprising a slide having a portion thereon adapted to alternately block said chute and to permit a workpiece to move therefrom to a feeding position, and then feed the workpiece between the dies, spring means urging said slide toward a feeding position, a rotatable cam and a lever actuated by said cam, a flexible connection between said lever and said slide, whereby upon rotation of said cam said cam and lever first permit said slide to advance in a feeding stroke under the bias of said spring means and then retract said slide through said flexible connection to store energy in said spring means, said flexible connection being ineffective to transmit a driving force on said slide during a work feeding stroke of said slide.

2. The mechanism of claim 1 wherein said flexible means connected between said lever and said slide is a cable.

3. The mechanism of claim 2 further including means biasing one end of said lever into engagement with said cam, said cable being connected to the other end of said lever, said cam being so constructed and contoured that upon rotation thereof it permits said lever to pivot in a first direction to allow said slide to move in a feeding stroke and pivot in a second direction to retract. said slide.

4. The mechanism of claim 3 wherein the effective length of said other end of said lever is adjustable.

5. The mechanism of claim 2 wherein the effective length of said cable is adjustable. 

1. A feed mechanism for a thread roller which includes first and second rolling dies, one of said dies being movable relative to the other, and a chute for delivering workpieces to a position for rolling between the dies, comprising a slide having a portion thereon adapted to alternately block said chute and to permit a workpiece to move therefrom to a feeding position, and then feed the workpiece between the dies, spring means urging said slide toward a feeding position, a rotatable cam and a lever actuated by said cam, a flexible connection between said lever and said slide, whereby upon rotation of said cam said cam and lever first permit said slide to advance in a feeding stroke under the bias of said spring means and then retract said slide through said flexible connection to store energy in said spring means, said flexible connection being ineffective to transmit a driving force on said slide during a work feeding stroke of said slide.
 2. The mechanism of claim 1 wherein said flexible means connected between said lever and said slide is a cable.
 3. The mechanism of claim 2 further including means biasing one end of said lever into engagement with said cam, said cable being connected to the other end of said lever, said cam being so constructed and contoured that upon rotation thereof it permits said lever to pivot in a first direction to allow said slide to move in a feeding stroke and pivot in a second direction to retract said slide.
 4. The mechanism of claim 3 wherein the effective length of said other end of said lever is adjustable.
 5. The mechanism of claim 2 wherein the effective length of said cable is adjustable. 